hi
i have a lithium battery 3,7 volt
Unknown number amps
How can i know her ah number
or her amper
thank you

 

Discharge the battery into a known load, then measure the current and the time.

 

have you got a picture of the battery?

 

Discharge the battery into a known load, then measure the current and the time.

when i measure the current using mulltimetr not gev me Fixed number
Different numbers and then disappear

 

What is the resistance value of your load?

 

when i measure the current using mulltimetr not gev me Fixed number
Different numbers and then disappear

I'll bet you are shorting the battery by connecting the ammeter across it without a series load resistor....

 

have you got a picture of the battery?

Does not have data
just 3,7 volt

 

when i measure the current using mulltimetr not gev me Fixed number
Different numbers and then disappear

Then Ohms law tells me that you do not have a FIXED and CONSTANT load. An ammeter is a very low resistance, and could be damaged by doing what you did. Pick a resistor that will give you say 50 milliamps.

3.7 Volts / .050 Amperes ≈ 75 Ohms

The ammeter in series with the resistor goes across the battery terminals. Just to be extra safe estimate the power dissipated by the resistor as

(.050 Amperes)^2 * 75 Ohms ≈ 187.5 milliwats

So a quarter watt resistor will get warm but not explode.

 

What is the resistance value of your load?

resistance value 20 om

 

what is the number on the battery
?

 

I'll bet you are shorting the battery by connecting the ammeter across it without a series load resistor....

series load resistor 20 om shorting the battery

so what Suitable om using

 

l

what is the number on the battery
?

li-ion 18490 3.7 v
jo1.f18490ro4 340 13 12

thes all data in battry

 

looks like 1400maH @ 3.7V

http://www.aliexpress.com/item/Free...400mAh-Li-ion-Battery-2-packs/1780524637.html

 

I'm guessing that size is about 1500mAh.
If 20Ω (180mA load current) pulls that battery down immediately, then it is totally discharged, and needs charging before you do any more tests.

 

Then Ohms law tells me that you do not have a FIXED and CONSTANT load. An ammeter is a very low resistance, and could be damaged by doing what you did. Pick a resistor that will give you say 50 milliamps.

3.7 Volts / .050 Amperes ≈ 75 Ohms

The ammeter in series with the resistor goes across the battery terminals. Just to be extra safe estimate the power dissipated by the resistor as

(.050 Amperes)^2 * 75 Ohms ≈ 187.5 milliwats

So a quarter watt resistor will get warm but not explode.

i will do it

 

looks like 1400maH @ 3.7V

http://www.aliexpress.com/item/Free...400mAh-Li-ion-Battery-2-packs/1780524637.html

looks like 1400maH @ 3.7V

http://www.aliexpress.com/item/Free...400mAh-Li-ion-Battery-2-packs/1780524637.html

thank you

 

I'm guessing that size is about 1500mAh.
If 20Ω (180mA load current) pulls that battery down immediately, then it is totally discharged, and needs charging before you do any more tests.

i will do it thank you